Why doesn't the hpet show up in E820 map?

[poby]

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0xFEC00000 Len: 0x1000 type 2
0xFEE00000 Len: 0x1000 type 2
0xFFFC0000 Len: 0x40000 type 2

Why doesn't 0xFED00000 show up? It's the address used by the HPET which is enabled and working.

[Octocontrabass]

Either the ACPI specification doesn't require the HPET MMIO to be listed in the E820 address map, or there's a bug in the BIOS you're using.

If you need to know which of those it is, you'll have to refer to the ACPI specification.

[jnc100]

Why doesn't 0xFED00000 show up? It's the address used by the HPET which is enabled and working.

There's no reason it should. All 'Type 2' means is that this region should not be assigned to a device enumerated by ACPI using the ACPI _SRS method. In particular, it usually represents the location of the BIOS, APICs and fixed location legacy devices.

If for some reason you do wish to relocate the devices enumerated by ACPI (e.g. the HPET) using _SRS then you also need to keep a track yourself of where all devices are and avoid conflicts. The easiest thing to do, however, is simply leave them where the firmware put them.

Regards,
John.